Warm up

• The cell membrane is called phospholipid bilayer.– What is a phospholipid?– Which part of the phospholipid is hydrophobic?– Which part of the phospholipid is hydrophilic?– Define the term semi-permeable.

– Quiz in 5 min.

Notes: Passive TransportCh. 5 Pg 97-102

Cell Transport• Molecules cross

membrane in several ways– Some methods of

transport require energy and some do not.

– Depends molecules size, polarity, and concentration inside versus outside.

Cell Transport

• Small molecules and larger hydrophobic molecules move through bilayer easily.– e.g. O2, CO2, H2O

Cell Transport

• Ions, hydrophilic molecules, and large molecules do not move through the membrane on their own. – e.g. Na+, K+

Passive Transport

• Movement across the membrane WITHOUT the use of energy

Concentration Gradient

• Molecules have kinetic energy

• Concentration Gradient: difference between high and low concentration• Molecules move “down”

gradient without energy• Equilibrium - when all molecules are evenly spread out

• Draw this!

Types of Passive Transport

1. Diffusion: Movement of molecules from high to low concentrations.

Types of Passive Transport

2. Facilitated Diffusion: Molecules too big to move across the membrane use carrier proteins • Ex. Glucose

Types of Passive Transport

3. Osmosis: diffusion of water across membrane

• Water moves where there are more solutes.

• Solute: What gets dissolved.• Solvent: What the Solute

dissolves in.• Solution: The mixture of the

solute and the solvent.

Which way will the water move?

1. Hypotonic• More solutes inside the cell, water moves in • The cell swells

Types of Tonicity

Draw These

Animal Cell Plant Cell

Hypertonic

• More solutes outside the cell, water moves out the cell

• The cell shrinks

Animal Cell Plant Cell

Draw these!

Isotonic• Equal solutes inside and outside• Water moves in and out at the same rate• Cell stays the same

Animal Cell Plant CellDraw These!

http://www.youtube.com/watch?v=OYoaLzobQmk&index=2&list=PLexD8cl0p1-Z8r4WyQXQ6R6-Hg81nERSg